Namespaces shouldn't link to ReferenceSource

[JoshVarty]

Repro:
In any file add:

using System.Globalization;

If you press F12 on Globalization, it redirects to: http://referencesource.microsoft.com/mscorlib/a.html#7099ea39e44d5ca6

I think this occurs when a namespace is encapsulated entirely within a single assembly. http://source.roslyn.codeplex.com/#Microsoft.CodeAnalysis/Symbols/ISymbol.cs,68be6d663a53115a